I have a 35 inch BFG AT and 3.73 gear on 2004 F150 and wondering if my odometer is showing more or less miles than actual.
Do anybody know how to calculate? I'd like to know for my work, thanks!

 

If you havent had it reflashed, it is showing less than actual miles. I heard 10%, but you have to confirm that. The bigger tires make less rotations per mile, thus showing a lower speed and racking up less on the odometer.

 

uh i heard its more. not tryin to start an argument. i just heard that it adds more when you get bigger tires

 

You can check the difference here. http://www.miata.net/garage/tirecalc.html

 

From what to 3.73 gears? Taller tires = less revolutions per mile so it would show less mileage with bigger tires. Going from 4.10 to 3.73 would show less mileage as well. 3.55 to 3.73 would show more miles.

 

it is less. my 33's show 40mph at 45, radar tested. so i just use an 8/9 ratio when figuring out actual miles.

 

i have the same set up, 3.73 rear and 35 BFG A/Ts...my speedometer shows that im going 5 miles slower than i really am (25mph on speedo =30mph actual) and my miles show less on the odometer than actual...i have a GPS with MPH and a Trip odomoter..i think for every 10 miles on my odometer it skips 1 mile.

 

Thanks guys. My Edge shows 3 mph slower and Tomtom shows 6 mph slower than speedometer. I still think my odometer is showing less than actual...
Confusing.

 

Yes, your odometer IS showing less than actual.

 

my speedometer is slower than my actual speed but i got intrigued by the odomoter question and checked it today. over a 35 mile drive, my odometer was down 2.8 miles.